For uniform heating of objects to be annealed, which may have either a rectangular or a rounded cross-section, walking beam furnaces are used, since these ensure transportation of the objects with less damage than, for example, pusher-type furnaces, through which the objects are pushed.
To ensure maintenance of the shape and load-bearing capacity of the walking and fixed beams even at high furnace temperatures, they generally consist of pipes having a cooling medium flowing through them.
German Offenlegungsschrift 39 39 582 discloses a walking beam furnace in which the walking and fixed beams through which the cooling medium flows are provided with support members for the objects to be annealed, wherein locking elements received by the support members can easily be welded to the beams owing to their ready accessibility. In one embodiment the supporting surface is depressed towards the middle to form a trough. This provides fences in the depressed region as a means of fixing the position of objects to be heated, such as rounded material, which do not have flat bearing surfaces.
German Offenlegungsschrift 43 43 675 describes a walking beam furnace in which the cooled walking beams and/or fixed beams are fitted with short fastening members for support members which run obliquely to the direction of transport and have flat supporting surfaces for the objects to be annealed. These support members can be fixed at the same angle by removable pins fitting in bores at their ends or in eyes.
A substantial disadvantage of the walking beam furnaces described above is that their supporting surfaces are only designed for rounded or for flat material.